ELIZABETH F. LOFTUS has been researching how our memories work since the early 1970s. The professor of psychology and law now teaches at the University of California, Irvine. Quick to come from her lips is contempt for the analogy that human memory works like a computer hard disk, on which data are cleanly written and from which data are accurately read back. Loftus says our memories are routinely wrong.

Indeed, we all have forgotten where we placed our keys or blanked on a name. But that is not all. Our memories can change over time. In our mental images, we often paint ourselves in rosy colors and make the good old days nicer than they really were.